Network Device Identifies Packet Drop Sources via Error Rate Analysis

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Solution Overview

Problem

Current deterministic networking and Low Power and Lossy Networks (LLNs) face challenges in identifying and addressing packet drops caused by software defects, as existing routing protocols rely on dynamically computed link metrics that do not account for misbehaving nodes due to software issues.

Innovation Solution

A network device compares observed and expected packet error rates to identify a particular node as a source of packet drops by analyzing intersecting paths and initiating packet trains to pinpoint the issue, using machine learning to correlate network performance metrics and take corrective measures such as rerouting traffic to avoid the misbehaving node.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If dynamically computed link metrics (e.g., ETX values) are used to account for link quality degradation, then link quality can be adapted to changing environmental conditions, but packet drops caused by software defects at local devices cannot be detected or addressed

Engineering Contradiction:
Improvelink quality adaptationVSAvoidpacket delivery ratio
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the packet error rate analysis by dividing the network path into individual links and further segmenting by candidate misbehaving nodes. Each link's observed packet error rate is compared against expected rates, and nodes are individually evaluated as potential sources of packet drops by analyzing their specific contribution to errors on paths they traverse.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements feedback mechanisms where observed packet error rates are continuously monitored and compared against expected rates. When discrepancies are detected, the system feeds back this information to identify candidate misbehaving nodes and adjusts routing decisions accordingly, creating a closed-loop system that adapts to software defects.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If packet trains are initiated to pinpoint the source of packet drops, then measurement precision of node behavior can be improved, but network overhead and complexity increase

Engineering Contradiction:
Improvenode behavior detection accuracyVSAvoidpacket train initiation and analysis
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary actions by pre-calculating expected packet error rates for each link and path before actual packet transmission. These expected rates are stored and used as baseline references when initiating packet trains, allowing for rapid comparison and identification of anomalies without requiring complex real-time calculations during packet drop detection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies partial action by initiating packet trains only on paths where packet drops are suspected, rather than continuously monitoring all network paths. This selective approach reduces network overhead while maintaining sufficient measurement precision for identifying misbehaving nodes.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If routing protocols avoid misbehaving nodes identified by software defects, then network reliability improves, but path costs may increase due to suboptimal routing

Engineering Contradiction:
Improvenetwork reliabilityVSAvoidnetwork efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic routing where the network continuously adapts path selection based on real-time identification of misbehaving nodes. Routing paths are not static but dynamically adjusted to avoid nodes exhibiting software defects while maintaining efficiency by selecting from available optimal paths that do not include problematic nodes.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes routing parameters by modifying path selection criteria to include reliability metrics alongside traditional cost metrics. When misbehaving nodes are identified, the routing protocol adjusts its parameters to prioritize paths with higher reliability even if they have slightly higher traditional costs, achieving a balance between reliability and efficiency.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS9979619B2Identifying a source of packet drops in a network
Publication Date: 2018.05.22 CISCO TECHNOLOGY INC
  • US9979619B2 patent drawing
  • US9979619B2 patent drawing
  • US9979619B2 patent drawing

AI summary

In one embodiment, a device in a network performs a first comparison between observed and expected packet error rates for a first path in the network. The device identifies one or more intersecting paths in the network that intersect the first path. The device performs one or more additional comparisons between observed and expected packet error rates for the intersecting paths that intersect the first path. The device identifies a particular node along the first path as a source of packet drops based on the first comparison between the observed and expected packet error rates for the first path and on the one or more additional comparisons between the observed and expected packet error rates for the intersecting paths that intersect the first path.